Induction flow inlet fan



Jan. 6, 1931 E. ANDERSON INDUCTION FLOW INLET FAN Filed Sept. 21, \1929 -'5 Sheets-Sheet 1 INVENTOR EDWARD L. A/VDERSUM A TTORNEL Jan. 6, 1931. E. L. ANDERSON INDUCTION FLOW INLET FAN 5 Sheets-Sheet 2 INVENTOR EDWARDLANDERSON.

Filed Sept. 21. 1929 A TTORNE )"J Jan. 8, 1931.

FIG. 4.

E. L. ANDERSON INDUCTION FLOW INLET mu 3 [N VENTOR EDWARD LANDERSO/V. B Y

ATTORNEYJ Jan; s, 1931. E. L. ANDERSON 1,787,656

INDUCTION FLOW INLET FAN Filed Sept. 21, 1929 5 Sheets-Sheet 4 F/GJ.

JOMLM YJMAMLMJ A ITO/EVE )5 931. E. ANDERSON 1,787,556

INDUCTION FLOW INLET FAN Filed Sept. 21. 1929 5 Sheets-Sheet 5 FIG. 6.

N V E N TOR DWARD L. ANDERSON.

A TTORNE Y5 Paten'ted Jan. 6, 1931 UNITED STATES,

r OFFICE EDWARD L. ANDERSON, OF GROSSE ILE, 'MIGHIQAN ASSIGNOR TO AMERICAN BLOWER CORPORATION, OF DETROIT, MICHIGAN} A GORPOEATION OF DELAWARE INDUCTION FLOW INLET FAN,

Application filed September'21, 1929,,{Serial K0. 394,184.

My invention relates to fans.

It is the object of my invention to provide such a construction that the internal pressure built up inside the fan will assist in drawing in air from outside of the fan and at the same time, will increase the efliciency of the fan;

by eliminating conflicting air currents and thereby increasing the effective area of the blades at or near the shroud of the wheel.

Heretofore, the leakage from the fan housing through the clearance gap between the inlet passageway of the housing and the fan wheel, due to the building up of pressure inside the housing, was either at right angles to the inflow of air from the inlet, or an angle greater than a right angle or an obtuse angle. uch a jet of air impingingiupon the inflow air caused a change in direction of inflow air and prevented the inflowing air from evenly filling the root of the blade of the fan. This left an ineflective section of the fan blade in which, there being no air movement of great moment, unevenness of distribution across the root of the blade was caused with a consequent drop in the efficiency of the apparatus.

Such a condition further arose when the cross jet of air from the clearance gap between the inlet and wheel interrupted the flow of inlet air causing a sufiicient leak of volume in the inlet side of the blade of the fan to permit of turbulence or reentry of the air.

It is the object of my invention to eliminate these conditions by providing such a construction so as to direct the air leakage, due to the necessary running clearance between the fan wheel and inlet, this air leakage being from the casing to the fan again in a direction parallel with the incoming air to induce the flow of incoming air. Therefore, I provide an injector action between the inside air and the outside air for inducing entrance of the latter into the fan and causing even distribution through the fan without turbulence.

Referring to the drawings:

Figure 1 is a rear elevation of the fan.

Figure 2 is a side elevation.

Figure3 a section of the line 33 of Figure 2.

Figure 4 is similar to Figure 3 except that a ,straight shroud is used. Figure 5 shows a construction by which the inlet cone or throat abuts the shroud of a .3, and the shroud is extended radially to pro-' vide a lap, but is again carried only to the center point.

Referring to the drawings in detail, 1 is the rear wall of the fan casing, and 2 is the front wall. The numeral 3 designates the scroll sidewall ofthe casing. The wall 2 is provided with an inlet vena contracta passageway member 4. This vena contracta inlet member defines a central air inlet passageway 5 which becomes the eye of the fan. The passageway 4 is divided at 6 and held by bolts 7.

This inlet passageway member 4 forms a constricted mouth for the inlet of the air which has a wall 8 directed inwardly and latterly, a restricted curved throat 9 and a flaring inner end 10. The fan consists of a hub 11 mounted on the shaft 12 with a back plate 13 supporting a plurality of blades 14. These blades carry an angular shroud 15 that is. directed inwardly and outwardly from the hub of the fan, (or if desired, a straight shroud normal to shaft) is directed inwardly and outwardly from the hub of the fan, terminating in an arcuate (or straight) lip lower edge 16, that is substantially parallel to the flared mouth 10 of the inlet tube 4,

spaced from it and in overlapping relation Thus, any leakage from in the area 18 and 19 is utilized to free the fan blades of turbulence and eddies and to induce the flow of air from the inlet opening, while at the same time insuring distribution of the air in that area designated 20 of the fanblades, which has heretofore been a dead area in the fan blades due to turbulence, low velocity and lack of air movement and air delivery to that portion of the fan blades. 21 is an internally extending member on the shroud.

I desire to comprehend within my invention such modifications as may be clearly embraced within my claims and the scope of my invention.

' Having thus fully described my invention, what I claim is new and desire to secure by Letters Patent, is:

1. In combination, in a fan of a fan housing, a restricted throat forming an inlet passageway into the housing, a fan adjacent said throat, and-an injector construction, for inducing pressure in the housing to reenter the fan and draw with it air through the inlet passageway in a thin stream of reentry air, said injector construction comprising adjacent surfaces of said fan and inlet passageway substantially parallel to one another and closely adjacent to one another.

2. In combination in a fan, a fan housing, a Venturi throat forming an inlet passageway for air, and a fan ,within said casing having a portion located adjacent to the inner margin of said Venturi throat but spaced therefrom between which air, already in the casing, may pass to induce the flow of air through the Venturi throat, said Venturi throat and overlapping fan portion being substantially in parallel spaced alignment.

3. In combination, a fan housing, an inwardly projecting air inlet passageway, a fan member having a plurality of blades rotating within said housing, exterior of but adjacent to said inlet passageway, a shroud on the ends of said blades for directing air from the inlet passageway through and over the blades into the casing, said shroud being located in partial overlapping engagement with the inner edge of said passageway but spaced therefrom, the inner edge of said passageway being flared and the adjacent edge of the shroud being flared to direct the injected air substantially parallel with the inner wall of the shroud.

4. In combination, a fan and a housing, a Venturi throat passageway inwardly directed into said housing, a fan having a plurality of blades whose longitudinal axes are parallel to the axes of the inlet passageway, said fan blades being adapted for drawing in air on the interior thereof and discharging it radially, a closed shroud on said fan blades towards the inlet side, said shroud depending in overlapping, spaced relationship with the inner end ofthe inlet passageway, whereby back pressure air behind the shroud may pass between the shroud and the inlet passageway to induce an even flow of air over the fan blades adjacent the inside of the shroud, the inner end of the inlet passageway and the lower edge of the shroud being flared, the remainder of the shroud being straight in cross section and extending diagonally towards the fan.

5. In a fan, a housing, means forming an inlet passageway, a fan in said housing, and cooperating means on said fan overlapping in spaced substantially parallel relationship the inner portion of said passageway, where by a portion of the air in the fan housing is reintroduced into the fan between the passageway and the cooperating means on the fan into the fan. i

6. In combination, a fan housing, a fan therein comprising a shaft, a supporting Wall for fan blades mounted thereon, a plurality of fan blades mounted on said wall, an annular shroud member joining the other ends of said fan blades and having a central aperture communicating with the interior of said blades, an inlet passageway extending from the side of the fan casing to a oint within said shroud in spaced, closely a jacent, parallel relationship, said shroud and inlet passageway having their overlapping edges arcuate in section.

7. In combination, a fan housing, a fan therein comprising a shaft, a supporting Wall for fan blades mounted thereon, a plurality of fan blades mounted on said Wall, an annular shroud member joining the other ends of said fan blades and having a central aperture communicatingwith the interior of said blades, an inlet passageway extending from the side of the fan casing to a point within said shroud in spaced, closely adjacent, parallel relationship, said shroud and inlet passageway having their overlapping edges arcuate in section, said inlet passageway having a restricted throat and the inner end of said passageway expanding from said restricted throat to a point Within the fan.

8. In a fan, the combination of a plurality of rotating fan blades, a housing therefor, an inlet passageway formed in said housing adjacent the margins of said blades, and an injector for utilizing pressure in the fan housing for inducing air flow evenly over the fan blades, said injector comprising overlapping substantially parallel spaced portions of said inlet member and said fan.

In testimony whereof, I aflix my signature.

EDWARD L. ANDERSON. 

